Vehicle seat

ABSTRACT

Provided is a vehicle seat which is capable of easily mounting a reclining mechanism mounted to a seat back frame and a resin molding part of a seat cushion frame and realizes an improved workability. A reclining mechanism arranged on the lower end side of a seat back frame and the rear end side of a seat cushion frame are coupled with a coupling member, a metal member is integrally formed on the rear end side of the seat cushion frame, an upper part of the coupling member is mounted to the reclining mechanism, and a lower part of the coupling member is welded and connected to the metal member provided on the rear end side of the seat back frame.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage Entry application of PCTApplication No. PCT/JP2013/058131, filed Mar. 21, 2013, which claims thepriority benefit of Japanese Patent Application No. 2012-072472, filedMar. 27, 2012, the contents of all being incorporated herein byreference.

BACKGROUND

Disclosed herein is a vehicle seat, and, particularly, a vehicle seatprovided with a reclining mechanism for supporting a seat back frame ina rotatable state, and a seat cushion frame having a resin molding partmade of a resin material.

Among vehicle seats, in order to reduce weight, some seat back frames orseat cushion frames are molded by a resin material such as plastic, inpart or in whole.

As an example of such a vehicle seat, there is a known vehicle seatwhich is provided with a reclining mechanism for supporting a seat backincluding a seat back frame in a rotatable state relative to a seatcushion and in which, for example, a seat cushion frame coupled to thereclining mechanism is molded by a resin material.

As such a configuration example, for example, there is proposed avehicle seat in which the whole seat cushion frame is molded as anintegral member by a composite material consisting of a thermoplasticmatrix and reinforcing fibers, or the like.

As thus described, in the seat cushion frame reduced in weight,generally, fastening and fixing by a fastening member such as a bolt istypical for mounting peripheral members (refer to Japanese PatentDocument No. 2002-034706 A (“the '706 Document”)).

A vehicle seat described in the '706 Document is provided with a cushionframe which may be formed of a reinforced resin to reduce weight asdisclosed therein.

In frame sides constituting the vehicle seat, bolt holes are formed, andin the bolt holes, hinge brackets of a reclining device are assembled bybolting, respectively.

In this way, the reclining device is mounted to the cushion frame bybolting (of the hinge brackets).

However, as with the vehicle seat described in the '706 Document, ifbolting is performed when mounting other components (for example, areclining mechanism) to the cushion frame, there is a problem that manyworking processes are required and workability is poor.

Accordingly, in manufacturing vehicle seats, it has been stronglydemanded to improve workability in the other components mounting processby mounting a reclining mechanism to a resin molding part molded by aresin material in a seat cushion frame more easily.

In addition, along with this, a technique in which the number ofcomponents is reduced and which is advantageous also in cost has beendemanded.

Further, in order to reduce weight of frame, in constituting the seatcushion frame by a resin, it is necessary to secure the rigidity of thereclining mechanism and its mounting point (the mounting point in theseat cushion frame), that is, the mounting rigidity of the recliningmechanism to the seat cushion frame and the rigidity of the peripheralpart mounting point while making the mounting of the reclining mechanismeasier.

SUMMARY

An object of various embodiments disclosed herein is to provide avehicle seat which, in the manufacturing process, is capable of easilymounting a reclining mechanism mounted to a seat back frame and a resinmolding part of a seat cushion frame and realizes an improvedworkability.

In addition, other object is to provide a vehicle seat in which themounting rigidity of the reclining mechanism and the periphery of theseat cushion frame is secured while making the coupling of the recliningmechanism and the seat cushion frame easier.

In addition, other object is to provide a vehicle seat in which anincrease of the number of components is suppressed while separatelyusing a component for mounting the reclining mechanism.

Accordingly, the above problems are solved by a vehicle seat having aseat back frame on which a reclining mechanism is arranged on a lowerpart thereof, and a seat cushion frame made of a resin material at leastpartly, in which the reclining mechanism arranged on a lower end side ofthe seat back frame and a rear end side of the seat cushion frame arecoupled with a metallic coupling member, a metal member is integrallyformed on the rear end side of the seat cushion frame, an upper part ofthe coupling member is mounted to the reclining mechanism, and a lowerpart of the coupling member is welded and connected to the metal memberprovided on the rear end side of the seat back frame.

As thus configured, the reclining mechanism mounted to the seat backframe and the seat cushion frame can be coupled by a welding connectionvia the coupling member.

In other words, this design is configured so that the metallic couplingmember and the metal member integrally formed on the rear end side ofthe seat cushion frame can be welded and connected.

Therefore, for example, it is unnecessary to perform the fixing bybolting, and it is possible to reduce working processes. Then, alongwith this, mounting workability is improved.

In addition, the welding connection is performed by using the couplingmember, so that it is unnecessary to use fastening members (for example,bolts or the like) other than the coupling member and consequently thenumber of components can be reduced.

If the reclining mechanism also is connected to the seat back frame bywelding, differently from the case where the reclining mechanism isover-molded when molding a resin molding part of the seat back frame,the structure in which the reclining mechanism is mounted to the resinmolding part is not complicated, mounting of the reclining mechanism canbe easily performed, and further workability is improved.

In addition, in the above vehicle seat, preferably, the metal member isarranged on at least a part of an outside surface of a rear end of theseat cushion frame and on at least a part of an upper side surfaceextending while bending inward from an upper part of the outsidesurface, and the coupling member is welded and connected at a coveringportion in a state that the metal member portion arranged on the outsidesurface and the upper side surface of the rear end of the seat cushionframe is covered.

As thus configured, on the outside surface and the upper side surface ofthe seat cushion frame, the coupling member and the metal member arecoupled at the portion where they are layered, so that the mountingrigidity of the coupling member is improved.

In addition, in the above vehicle seat, preferably, the seat cushionframe is provided with a height adjustment mechanism mounting part towhich a height adjustment mechanism for displacing a height of the seatcushion frame with respect to a vehicle floor is mounted, and thecoupling member extends to a position aligned with at least a part ofthe height adjustment mechanism mounting part in an up and downdirection in a state that the coupling member is welded to the rear endside of the seat cushion frame.

As thus configured, the rigidity in the vicinity of the heightadjustment mechanism mounting part is improved.

In addition, specifically in the above configuration, preferably, theheight adjustment mechanism is configured as a link mechanism, theheight adjustment mechanism mounting part is provided as a hole part inwhich a link central axis or a link driving member is arranged, and themetal member extends to a position where the height adjustment mechanismmounting part is provided.

As thus configured, the rigidity of the hole part is improved, and themounting rigidity of the link or the mounting rigidity of the linkdriving member (for example, a brake mechanism or the like) is improved.

In addition, in the above vehicle seat, preferably, the coupling memberis configured by being curved in such a manner that a mounting pointthereof to the seat cushion frame extends toward a front upper side ofthe seat cushion frame in a state that the coupling member is welded tothe rear end side of the seat cushion frame, and the metal member isconfigured to be arranged by being curved to align with a shape of themounting point of the coupling member to the seat cushion frame.

As thus configured, the welding area can be secured large compared tothe case where welding point is linearly formed, so that the mountingrigidity of the coupling member is improved.

In addition, in the above vehicle seat, the seat cushion frame isprovided with a height adjustment mechanism mounting part to which aheight adjustment mechanism for displacing a height of the seat cushionframe with respect to a vehicle floor is mounted, and the metal memberextends to a position aligned with at least a part of the heightadjustment mechanism mounting part in an up and down direction.

As thus configured, the rigidity in the vicinity of the heightadjustment mechanism mounting part is improved.

In addition, in the above vehicle seat, preferably, the coupling memberand the reclining mechanism are welded and connected, an upper part ofthe coupling member is formed to align with a shape of the recliningmechanism, and the welded portion between the coupling member and thereclining mechanism is configured to align with the shape of thereclining mechanism.

As thus configured, the distance between the welded portion and thereclining mechanism can be secured in the coupling member so that therigidity of the coupling member is improved.

In addition, the mounting rigidity of the coupling member is improved aswell.

In addition, in the above vehicle seat, preferably, the recliningmechanism is mounted to the upper part of the coupling member, the seatcushion frame is welded and connected to the lower part of the couplingmember, and the lower part of the coupling member is configured largerthan the upper part thereof.

As thus configured, the welding area can be secured large so that themounting rigidity is improved.

Further, in the above vehicle seat, preferably, the seat cushion frameis provided with a height adjustment mechanism mounting part to which aheight adjustment mechanism for displacing a height of the seat cushionframe with respect to a vehicle floor is mounted, the height adjustmentmechanism is configured as a link mechanism, and the height adjustmentmechanism mounting part is provided as a hole part in which a linkcentral axis or a link driving member is arranged, and it is preferablethat the lower part of the coupling member is curved to escape to a rearside with respect to the height adjustment mechanism mounting part whenmounted to the rear end side of the seat cushion frame because theinhibition of assembling work of the height adjustment mechanism can beeffectively prevented.

Furthermore, in the above vehicle seat, preferably, the seat cushionframe is provided with a height adjustment mechanism mounting part towhich a height adjustment mechanism for displacing a height of the seatcushion frame with respect to a vehicle floor is mounted, the heightadjustment mechanism is configured as a link mechanism, and the heightadjustment mechanism mounting part is formed as a hole part in which alink central axis or a link driving member is arranged, and it ispreferable that the metal member provided on the rear end side of theseat back frame extends to a position surrounding the height adjustmentmechanism mounting part because the rigidity of the height adjustmentmechanism mounting part (the peripheral part of the hole part) isimproved.

Furthermore, in the above vehicle seat, preferably, the seat cushionframe is provided with a height adjustment mechanism configured as alink mechanism for displacing the height of the seat cushion frame withrespect to a vehicle floor, a height adjustment mechanism is providedwith a brake pinion mechanism for restricting an action of the linkmechanism, and the seat cushion frame is provided with a brake memberarrangement hole in which the brake pinion mechanism is arranged, and itis preferable that the metal member provided on the rear end side of theseat back frame extends to a position surrounding the brake memberarrangement hole because the rigidity in the periphery of the mountingpart for the brake pinion mechanism is improved.

Furthermore, in the above vehicle seat, preferably, the metal member isarranged on at least a part of an outside surface of a rear end of theseat cushion frame and on at least a part of an upper side surfaceextending and bending inward from an upper part of the outside surface,at least a part of the metal member is formed as a convex partprotruding outward, at least a part of the convex part is exposedoutward, and the coupling member is welded and connected to an outwardexposed portion of the convex part in a state that the metal memberportion arranged on the outside surface and the upper side surface ofthe rear end of the seat cushion frame is covered.

As thus configured, the (welding) mounting rigidity is improved, and therigidity in the periphery of the welded part is also improved.

Furthermore, in the above vehicle seat, preferably, the metal member isconfigured as an iron pin having a head and a leg, the iron pin is fixedto the seat back frame in such a manner that the head is arranged inwardand a free end side of the leg is arranged outward, the coupling memberis provided with a coupling member-side iron pin through-hole throughwhich the leg passes, and the coupling member is mounted to the seatcushion frame by a welding connection in a contact part of the leg andthe coupling member-side iron pin through-hole in a state that the metalmember portion arranged on an outside surface and an upper side surfaceof a rear end of the seat cushion frame is covered and the leg isinserted through the coupling member-side iron pin through-hole.

As thus configured, the welding mounting rigidity is improved, therigidity in the periphery of the welded part is also improved, and, inaddition to this, the connection of the seat cushion frame and thecoupling member is facilitated.

Furthermore, in the above vehicle seat, preferably, the metal member isarranged on at least a part of the outside surface of a rear end of theseat cushion frame and on at least a part of an upper side surfaceextending and bending inward from an upper part of the outside surfaceand extends from a back toward a front of the outside surface whileavoiding an upper edge part and a lower edge part of the outsidesurface, and the coupling member is welded and connected at a coveringportion in a state that the metal member portion arranged on the outsidesurface and the upper side surface of the rear end of the seat cushionframe is covered.

As thus configured, the coupling member and the metal member are coupledat the portion where these members are layered on the outside surfaceand the upper side surface so that the mounting rigidity of the couplingmember is improved, and the rigidity is improved because the line fromthe back toward the front of the outside surface of the cushion frame isreinforced.

Then, if the mounting parts (for example, mounting holes or the like)for components or the like are formed in the portion extending from theback toward the front, that portion is strengthened and the rigidity isimproved.

According to the vehicle seat of an embodiment, when coupling thereclining mechanism mounted to the seat back frame and the seat cushionframe, for example, it is unnecessary to perform the bolting or thelike, and it is possible to reduce working processes. Then, along withthis, the mounting workability is improved.

In other words, the reclining mechanism mounted to the seat back frameand the seat cushion frame can be easily coupled.

In addition, the welding connection is performed by using the couplingmember, so that it is unnecessary to use fastening members (for example,bolts or the like) other than the coupling member and consequently thenumber of components can be reduced.

According to the vehicle seat of an embodiment, on the outside surfaceand the upper side surface of the seat cushion frame, the coupling isperformed at the portion where they are layered so that the mountingrigidity of the coupling member is improved.

According to the vehicle seat of an embodiment, the rigidity in thevicinity of the height adjustment mechanism mounting part is improved.

According to the vehicle seat of an embodiment, the mounting rigidity ofthe link or the mounting rigidity of the link driving member (forexample, a brake mechanism or the like) is improved.

According to the vehicle seat of an embodiment, the welding area can besecured large compared to the case where welding point is linearlyformed, so that the mounting rigidity of the coupling member isimproved.

According to the vehicle seat of an embodiment, the rigidity in thevicinity of the height adjustment mechanism mounting part is improved.

According to the vehicle seat of an embodiment, the distance between thewelded portion and the reclining mechanism can be secured so that boththe rigidity of the coupling member and the mounting rigidity of thecoupling member are improved.

According to the vehicle seat of an embodiment, the welding area can besecured large, so that the mounting rigidity is improved.

According to the vehicle seat of an embodiment, the inhibition ofassembling work of the height adjustment mechanism can be effectivelyprevented.

According to the vehicle seat of an embodiment, the rigidity of theheight adjustment mechanism mounting part (the peripheral part of thehole part) is improved.

According to the vehicle seat of an embodiment, the rigidity in theperiphery of the mounting part for the brake pinion mechanism isimproved.

According to the vehicle seat of an embodiment, the welding mountingrigidity is improved, and the rigidity in the periphery of the weldedpart is also improved.

According to the vehicle seat of an embodiment, the welding mountingrigidity is improved, the rigidity in the periphery of the welded partis also improved, and in addition to this, the connection of the seatcushion frame and the coupling member is facilitated.

According to the vehicle seat of an embodiment, the mounting rigidity ofthe coupling member is improved, and the rigidity of the side surfaceportion of the seat cushion frame is improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view of a vehicle seat according toone embodiment of the present invention.

FIG. 2 is a schematic perspective view showing a frame of the vehicleseat according to the embodiment of the present invention.

FIG. 3 is a schematic side view showing the frame of the vehicle seataccording to the embodiment of the present invention.

FIG. 4 is a schematic side view showing an internal structure of areclining mechanism according to the embodiment of the presentinvention.

FIG. 5 is an enlarged perspective view of the periphery of the recliningmechanism of FIG. 2.

FIG. 6 is a schematic perspective view showing an example of the shapeof a seat back frame according to the embodiment of the presentinvention.

FIG. 7 is a schematic perspective view showing the reclining mechanismaccording to the embodiment of the present invention.

FIG. 8 is a typical perspective view of a seat cushion frame accordingto the embodiment of the present invention.

FIG. 9 is an explanatory side view showing a height adjustment mechanismaccording to the embodiment of the present invention in a state when thevehicle seat is in a normal position.

FIG. 10 is an explanatory side view showing the height adjustmentmechanism according to the embodiment of the present invention in astate when the vehicle seat is in a raised position.

FIG. 11 is an enlarged explanatory perspective view of the periphery ofthe reclining mechanism according to the embodiment of the presentinvention.

FIG. 12 is a cross-sectional explanatory view taken along the line A-Aof FIG. 11.

FIG. 13 is an explanatory perspective view showing an assembling processof the reclining mechanism according to the embodiment of the presentinvention.

FIG. 14 is a cross-sectional explanatory view of a corresponding portionof the A-A line, showing the assembled state of FIG. 13.

FIG. 15 is an explanatory perspective view showing the assemblingprocess of the reclining mechanism according to the embodiment of thepresent invention.

FIG. 16 is a cross-sectional explanatory view of the correspondingportion of the A-A line, showing the assembled state of FIG. 15.

FIG. 17 is a typical explanatory view showing a different materialwelding connection technique.

FIG. 18 is an explanatory perspective view showing the assemblingprocess of the reclining mechanism according to the embodiment of thepresent invention.

FIG. 19 is a cross-sectional explanatory view of the correspondingportion of the A-A line, showing the assembled state of FIG. 18.

FIG. 20 is an enlarged explanatory perspective view of the vicinity ofthe welded part of a side part frame according to the embodiment of thepresent invention.

FIGS. 21A & B are cross-sectional explanatory views taken along the lineB-B of FIG. 20.

FIG. 22 is an explanatory perspective view showing a first modificationexample.

FIG. 23A-C are a cross-sectional explanatory views taken along the lineC-C of FIG. 22.

FIG. 24 is an explanatory perspective view showing a second modificationexample.

FIG. 25 is an explanatory perspective view showing a third modificationexample.

FIG. 26 is an explanatory side view showing a fourth modificationexample.

FIG. 27 is an explanatory side view showing a fifth modificationexample.

DETAILED DESCRIPTION

Hereinafter, a vehicle seat according to one embodiment (hereinafter,referred to as the present embodiment) of the present invention will bedescribed with reference to the drawings. The embodiment described belowis merely an example to facilitate understanding of the presentinvention, and the present invention is not limited thereto. That is,the shape, dimension, arrangement and the like of the members describedbelow can be changed and improved without departing from the gist of thepresent invention, and as a matter of course, the present inventionincludes equivalents thereof.

In addition, in the following description, the front to back directionis a direction corresponding to a traveling direction of a vehicle, thewidth direction is a direction along the lateral width of the vehicleand corresponds to the width direction of the vehicle seat of thepresent invention, and the up and down direction is the up and downdirection of the vehicle.

FIGS. 1 to 21 show one embodiment of the present invention, and theembodiment of the present invention will be described below withreference to these figures.

In addition, FIGS. 22 to 26 show a first modification example to a fifthmodification example respectively, and the respective modificationexamples will be described with reference to these figures afterdescribing the embodiment.

In the cross-sectional explanatory views of FIGS. 12, 14, 16, and 19, inorder to simplify the illustration, an internal structure of a recliningmechanism is omitted, and a case of the reclining mechanism also isillustrated in a slightly simplified manner.

As shown in FIG. 1, a vehicle seat S according to the present embodimentis configured by a seat back S1, a seat cushion S2, and a headrest S3,and the seat back S1 and the seat cushion S2 are respectively configuredby disposing cushion pads 1 a, 2 a on frames 1, 2 and covering them withskin materials 1 b, 2 b.

The headrest S3 is configured by disposing a cushion pad 3 a on a corematerial (not shown) and covering them with a skin material 3 b, andsupported by a headrest pillar HP mounted to the seat back frame 1.

As shown in FIGS. 2 and 3, the frame of the vehicle seat S according tothe present embodiment has the seat back frame 1 constituting the seatback S1 and the seat cushion frame 2 constituting the seat cushion S2,as main constituent elements.

The seat cushion frame 2 is of a substantially square shape in planview, and mounted to the vehicle floor via a slide rail mechanism 4 forslidably moving the vehicle seat S in the front to back direction and aheight adjustment mechanism 5 for moving the vehicle seat S in the upand down direction

The seat back frame 1 is of a substantially square shape in plan view,and integrally formed by a carbon fiber reinforced plastic (CFRP) as aresin material in the present embodiment.

The seat back frame 1 is supported by coupling a lower end thereof to arear end of the seat cushion frame 2 via a reclining mechanism 10 and acoupling bracket 9 mounted thereto.

In such a state, the seat back frame 1 can be rotated in the directionshown by an arrow in FIG. 3 relative to the seat cushion frame 2.

The periphery of the coupling portion of the seat cushion frame 2 andthe seat back frame 1 will be described in detail later because thatportion is a main configuration including the configuration of thereclining mechanism 10 and the coupling bracket 9.

The reclining mechanism 10 is mounted to a predetermined position of theseat back frame 1 for supporting the seat back frame 1 in a rotatablestate. The reclining mechanism 10 has a reclining mechanism main body 11that drives when rotating the seat back frame 1, and a case 12 housingthe reclining mechanism main body 11, as main constituent elements.

As to the reclining mechanism main body 11, a known configuration forrotatably supporting the seat back frame 1 is adopted. As an example, asliding lock member 15 is provided as shown in FIG. 4, and a lock gearpart 14 mounted to the sliding lock member 15 is engaged with anddisengaged from an engaging gear 13 by the moving action of the slidinglock member 15.

By such a reclining mechanism main body 11, it is possible to switch thestate of the seat back frame 1 between a locked state in which it isfixed to the seat cushion frame 2 and an unlocked state in which it canbe rotated relative to the seat cushion frame 2.

Specifically, in the present embodiment, the case 12 housing thereclining mechanism main body 11 is of a substantially cylindrical outershape, and configured by combining an outer case piece 12 a and an innercase piece 12 b shown in FIG. 7, for example.

The outer case piece 12 a and the inner case piece 12 b are both made ofmetal. The outer case piece 12 a is connected to the seat cushion frame2 side, the aforementioned engaging gear 13 is formed on an innerperipheral face thereof, and the aforementioned sliding lock member 15is provided further on the inside thereof.

On the other hand, the inner case piece 12 b is connected to the seatback frame 1 side, and a pair of path regulating parts 16, 16 regulatinga moving path of the sliding lock member 15 are disposed on the insidethereof in a state that the sliding lock member 15 is sandwichedtherebetween.

In addition, the sliding lock member 15 is formed with a cam surface 17,and a cam body 18 abutting on the cam surface 17 is mounted in a fixedstate to a rotary shaft 20 passing through the inner case piece 12 b andentering the case.

In the reclining mechanism 10 thus configured, in a normal time, thesliding lock member 15 is disposed in a position where the lock gearpart 14 and the engaging gear 13 are engaged with each other, and thestate of the seat back frame 1 is in the locked state.

In such a state, when an operating lever T (see FIG. 3) is operated, therotary shaft 20 is rotated by the operation, and in conjunction withthis, the cam body 18 is rotated. The cam body 18 in a rotating stateabuts on the cam surface 17, and thereby the sliding lock member 15moves in a direction away from the engaging gear 13 between the pathregulating parts 16, 16.

As a result, the lock gear part 14 is disengaged from the engaging gear13, and the state of the seat back frame 1 is in the unlocked state.

Then, while the state of the seat back frame 1 is in the unlocked state,an occupant can tilt the seat back S1 backward. If the operating lever Tis released at the time when the backward-tilt angle reaches a desiredangle, the cam body 18 returns by a spring body 19 to the originalposition, namely, the position at locking, and the sliding lock member15 moves between the path regulating parts 16, 16 toward the engaginggear 13.

As a result, when the operation of the operating lever T ends, the lockgear part 14 engages again to the engaging gear 13, and the state of theseat back frame 1 returns to the locked state.

Although the coupling bracket 9 is welded or adhered to the recliningmechanism 10 and the reclining mechanism 10 is coupled to the seatcushion frame 2 via the coupling bracket 9, this configuration will bedescribed in detail later.

And now, as shown in FIG. 5, a spiral spring P as an elastic member ishung on the lower end of the seat back frame 1 connected to thereclining mechanism 10 and the rear end of the seat cushion frame 2.

The spiral spring P biases the seat back frame 1 to be rotated forwardlywhen the state of the seat back frame 1 is in the unlocked state and theseat back S1 is in the backward-tilting state, and one end P1 thereof islocked to a locking part K1 provided on the seat back frame 1 side.

Here, the locking part K1 is formed by a sheet metal member fixed to aside frame 22 of the seat back frame 1, for example, and is locked byhooking the one end P1 of the spiral spring P to the bent portionthereof to extend outward in the width direction.

The other end P2 of the spiral spring P is locked to a locking part K2provided on the seat cushion frame 2 side, and the locking part K2 alsohas a portion extending outward in the width direction, and locks theother end P2 of the spiral spring P by hooking the other end P2 of thespiral spring P to that portion.

Next, the configuration of the above-mentioned seat back frame 1 will bedescribed in greater detail.

As previously described, the seat back frame 1 is made of CFRP, andintegrally molded by way of metal molding in the present embodiment.However, it is not limited thereto, and the seat back frame 1 may bemolded by a resin material other than CFRP. Alternatively, the seat backframe 1 may be configured by way of a molding method other than metalmolding, for example, by layering sheets made of a resin material to befitted to the shape of frame.

As to the shape of the seat back frame 1, it is a substantially squareouter shape in plan view, as previously described. Specifically, theseat back frame 1 has an upper frame 21 extending along the widthdirection, a pair of side frames 22, 22 extending downwardly from bothends of the width direction of the upper frame 21, and a lower frame 23coupling the lower ends of the side frames 22.

The upper frame 21 is formed slightly wider in the up and downdirection, and in the present embodiment, the cross section whose normaldirection is the width direction has a closed cross section structure,that is, the cross-sectional shape is a hollow rectangular shape.

Each of the pair of side frames 22, 22 is widened asymptotically fromthe upper part toward the lower part, and the lower end thereof has asemicircular shape when viewed from the width direction.

In addition, as to each side frame 22, the cross-sectional shape whosenormal direction is the up and down direction has a closed cross sectionstructure to a halfway position in the up and down direction.

On the other hand, as to the lower end of each side frame 22, itscross-sectional shape is not a closed cross-sectional shape, and aninner portion in the width direction is formed in an opening shape.

This is caused by extracting the seat back frame 1 which is a moldedproduct from the mold in the metal molding process.

However, each side frame 22 is not limited to the above shape, may havea closed cross section structure to the lower end. In contrast, in eachside frame 22, the cross section structure may not be a closed crosssection structure from the upper end to the lower end.

In addition, a reclining mechanism arrangement hole 22 a is formed inthe lower end of each side frame 22, a circular ring shaped mountingbracket 10 a is mounted to that portion, and the reclining mechanism 10is arranged thereto via the mounting bracket 10 a.

The rotary shaft 20 is configured to protrude from a shaft hole formedin the reclining mechanism 10. Then, the rotary shaft 20 is disposedbetween the side frames 22, 22 in a state that the axial direction isalong the width direction, and the end of the rotary shaft 20 protrudesoutward in the width direction from an outside surface 22 b of the sideframe 22 through the shaft hole.

Then, the operating lever T is mounted to a position further out thanthe reclining mechanism 10.

As to the number of the reclining mechanisms 10, two recliningmechanisms 10 may be provided to be disposed at both sides in the widthdirection of the vehicle seat S, or one reclining mechanism 10 may beprovided to be disposed at one side in the width direction of thevehicle seat S.

The lower frame 23 is provided to wrap around a front face from the rearend of the lower end of each side frame 22, and has a substantiallyJ-shape in side view.

In the seat back frame 1 thus configured, the aforementioned recliningmechanism 10 is mounted to the side frame 22.

In other words, the reclining mechanism 10 is mounted to the outsidesurface 22 b facing the outside in the width direction, morespecifically, to the lower end in which the reclining mechanismarrangement hole 22 a is formed, of the side surface of the side frame22.

In the present embodiment, the whole seat back frame 1 including theside frame 22 is molded by CFRP as a resin material but is not limitedthereto, and of the seat back frame 1, at least a portion to which thereclining mechanism 10 is mounted may be made of a resin material.

In addition, in the present embodiment, the seat back frame 1 isintegrally molded by metal molding but is not limited thereto, and theseat back frame 1 may be configured by separately molding a frontportion (a front shell) and a rear portion (a rear shell) of the seatback frame 1 and thereafter combining the both shells.

More specifically, as shown in FIG. 8, the aforementioned seat cushionframe 2 is provided with a pair of side part frames 6 a, 6 b located onboth ends of the width direction of the seat cushion frame 2, a rear endside coupling part 7 coupling the rear ends of the side part frames 6 a,6 b, and a front end side coupling part 8 coupling the front ends of theside part frames 6 a, 6 b.

The respective parts of the seat cushion frame 2 described above areintegrally molded by CFRP, as previously described.

In the present embodiment, the whole seat cushion frame 2 including theside part frames 6 a, 6 b is molded by CFRP as a resin material but isnot limited thereto, and of the seat cushion frame 2, at least the sidepart frames 6 a, 6 b may be made of a resin material, or of the sidepart frames 6 a, 6 b, at least a portion to which the coupling bracket 9is mounted may be made of a resin material in part.

In addition, the seat cushion frame 2 according to the presentembodiment is manufactured by metal molding but is not limited thereto,and the seat cushion frame 2 may be molded by a molding method otherthan metal molding, for example, by layering sheets made of a resinmaterial to be fitted to the shape of frame. In addition, the materialof the seat cushion frame 2 is not limited to CFRP, and may be otherresin materials.

Further, in the present embodiment, although the whole seat cushionframe 2 is molded by CFRP as a resin material, an iron plate piece I2 isinsert-molded in the rear end of the side part frames 6 a, 6 b.

In other words, in the present embodiment, in the coupling portion withthe coupling bracket 9, the iron plate piece I2 is insert-molded inCFRP.

This is effective for facilitating the laser welding of the couplingbracket 9 configured as a metal member, and for enhancing the rigidityof that area.

The details of the area where the iron plate piece I2 is inserted or thelike will be described in detail later because that area is a mainconfiguration.

Each of the pair of the side part frames 6 a, 6 b is elongated along thefront to back direction of the vehicle seat S, and the seat back frame1, more specifically, the side frame 22 of the seat back frame 1 ismounted to the inside of the rear end of the side part frames 6 a, 6 bvia the reclining mechanism 10.

In addition, of the rear end of the side part frames 6 a, 6 b, to theportion located below the portion to which the side frame 22 is mounted,a rear side link 30 described later is assembled.

Specifically, link assembling holes 51, 52 formed for assembling therear side link 30 are formed in the rear ends of the side part frames 6a, 6 b, respectively.

Further, a front side link 40 described later is assembled to the frontends of the side part frames 6 a, 6 b. Specifically, link assemblingholes 53, 54 formed for assembling the front side link 40 are formed inthe front ends of the side part frames 6 a, 6 b, respectively.

“The height adjustment mechanism mounting part formed as a hole part inwhich a link central axis is arranged” refers to the link assemblinghole 51 for example.

In addition, in the following description, among the pair of side partframes 6 a, 6 b, the side part frame 6 a located on one end of the widthdirection of the seat cushion frame 2 is referred to as the one endframe 6 a, and the side part frame 6 b located on the other end of thewidth direction of the seat cushion frame 2 in a state facing the oneend frame 6 a is referred to as the other end frame 6 b.

The rear end side coupling part 7 is molded slightly wider along thefront to back direction, and particularly in the present embodiment, atthe respective rear ends of the one end frame 6 a and the other endframe 6 b, the rear end side coupling part 7 is provided ahead of theportion to which the seat back frame 1 is mounted.

In addition, in the present embodiment, the rear end of the rear endside coupling part 7 extends toward the seat back frame 1 in a stateassembled to the respective rear ends of the one end frame 6 a and theother end frame 6 b.

More clearly, as shown in FIG. 2, the portion to which the seat backframe 1 is mounted is located in the uppermost part of the respectiverear ends of the one end frame 6 a and the other end frame 6 b, and therear end side coupling part 7 is provided at a position below theportion to which the seat back frame 1 is mounted.

On the other hand, as shown in FIG. 2, as to the rear end side couplingpart 7, its rear end position is located above the front end position.In other words, the rear end side coupling part 7 is formed in a tiltedstate with respect to the front to back direction, and its rear endextends toward the seat back frame 1 in a state mounted to therespective rear ends of the one end frame 6 a and the other end frame 6b.

Of the rear end side coupling part 7 formed in a tilted state, the facelocated ahead is a face supporting the waist of the occupant seated onthe vehicle seat S, and is a curved surface curved so that its centerpart is swelled backward. Thereby, a seating feeling when the occupantsits on the vehicle seat S is improved.

The front end side coupling part 8 is a portion corresponding to aso-called pan frame, and is expanded backwardly from the respectivefront ends of the one end frame 6 a and the other end frame 6 b.

In the present embodiment, as shown in FIG. 8, for the purpose ofimproving rigidity, concave parts 8 a, 8 b, 8 c are formed at aplurality of locations of the front end side coupling part 8.

The respective concave parts 8 a, 8 b, 8 c are formed by downwardlyrecessing the portion to which the concave parts 8 a, 8 b, 8 c areprovided, of the front end side coupling part 8.

The concave part 8 c located in the rearmost part among such concaveparts 8 a, 8 b, 8 c is a recess of a substantially square shape in planview formed in the center of the width direction of the rear end of thefront end side coupling part 8.

Then, in the seat cushion frame 2, an opening 2X of a rectangular shapein plan view is formed between the rear end side coupling part 7 and thefront end side coupling part 8, and a supporting member such as anS-spring laid above the opening 2X supports the hip of the occupantseated on the vehicle seat S.

In addition, of the front end side coupling part 8, the portion locatedbetween the concave part 8 c formed to be recessed in a substantiallysquare shape in plan view and the one end frame 6 a or the other endframe 6 b functions as a leg support part 8 d for supporting the legs ofthe occupant seated on the vehicle seat S.

Then, in the present embodiment, the leg support part 8 d is provided inthe portion with the heightened rigidity because it is located betweenthe concave part 8 c of a substantially square shape in plan view andthe one end frame 6 a or the other end frame 6 b of the front end sidecoupling part 8 so that the legs of the occupant can be stablysupported.

In addition, in the present embodiment, the whole seat cushion frame 2including the one end frame 6 a and the other end frame 6 b is molded byCFRP as a resin material but is not limited thereto, and of the seatcushion frame 2, at least the portions to which the rear side link 30and the front side link 40 are assembled may be made of a resinmaterial.

Next, the height adjustment mechanism 5 will be described.

The height adjustment mechanism 5 according to the present embodiment isdisposed between the seat cushion frame 2 and the slide rail mechanism 4in the up and down direction, and works by operating an operation part(not shown).

As to the configuration example of the height adjustment mechanism 5, asshown in FIGS. 9 and 10, the height adjustment mechanism 5 has, as mainconstituent elements, the rear side link 30 and the front side link 40as an example of rotating bodies.

The rear side link 30 is mounted to the respective rear ends of the oneend frame 6 a and the other end frame 6 b, and is rotatably supportedwith respect to a link support projection 4 b provided on a movable rail4 a of the slide rail mechanism 4.

The rear side link 30 is provided with a first rotatable arm 33 formedwith a sector gear 31, and when a driving force is transmitted from apinion gear 25 in conjunction with the above operation part to thesector gear 31, it rotates to move between the position shown in FIG. 9and the position shown in FIG. 10 by the driving force.

Briefly, the first rotatable arm 33 is rotatably journaled (is journaledby a second shaft pin 62) on the link support projection 4 b of themovable rail 4 a, and is rotatably journaled with respect to the one endframe 6 a by a first shaft pin 61 arranged in the link assembling hole51.

In addition, the first rotatable arm 33 is coupled to a second rotatablearm 34 (not shown) via a coupling pipe 35 (not shown), therefore thesecond rotatable arm 34 rotates integrally with the first rotatable arm33.

The second rotatable arm 34 (not shown) is disposed in a position facingthe first rotatable arm 33 in the width direction, in a state that theheight adjustment mechanism 5 is mounted to the seat cushion frame 2.The second rotatable arm 34 (not shown) is rotatably assembled to theother end frame 6 b at one end thereof when the height adjustmentmechanism 5 is mounted to the seat cushion frame 2. In addition, thesecond rotatable arm 34 is assembled to the link support projection 4 bof the movable rail 4 a at the other end thereof.

In other words, when the driving force is transmitted to the sector gear31 from the pinion gear 34, the first rotatable arm 33 and the secondrotatable arm 34 (not shown) rotate by the driving force, and the up anddown position on the rear side of the one end frame 6 a and the otherend frame 6 b is displaced.

In addition, front side link members 41 constituting the front side link40 are respectively mounted to the respective front ends of the one endframe 6 a and the other end frame 6 b.

The front side link 40 has a right and left symmetric structure, andtherefore the structure of one end of the right and left direction, thatis, of the width direction will be described below.

The front side link member 41 is rotatably supported (is journaled by asixth shaft pin 66) at one end thereof with respect to the link supportprojection 4 d provided on the movable rail 4 a of the slide railmechanism 4, and is rotatably mounted (is journaled by a fifth shaft pin65) at the other end thereof to the one end frame 6 a.

Therefore, the front side link member 41 rotates to move between theposition shown in FIG. 9 and the position shown in FIG. 10, inconjunction with the rotation of the rear side link 30.

As described above, the other end frame 6 b also is formed with asimilar link structure, and the front side link members 41 are paired.

Since the pair of front link members 41 are coupled by a coupling pipe42 (not shown), both members rotate integrally when rotating.

By the operation of the height adjustment mechanism 5 thus configured,the up and down position of the vehicle seat S can move from a normalposition shown in FIG. 9 to a raised position shown in FIG. 10, andconversely, can return from the raised position to the normal position.

Although the driving force from the operation part (not shown) istransmitted to the pinion gear 25 provided on the rear side link 30, thepinion gear 25 is provided with a brake mechanism.

As the brake mechanism, a known structure is adopted, that is, aso-called “brake pinion” is used.

Although a detailed description thereof will be omitted, the pinion gear25 is mounted to a drive shaft of a brake member for controlling therotation of the pinion gear 25.

The brake member maintains the operation part (not shown) in a neutralstate in a state that the operation part (not shown) is not operated (anormal state), and suppresses the rotation by braking the drive shaft.

On the other hand, when the operation part (not shown) is operated toinput the rotational force to the brake member, the brake member appliestorque so that the rotational force is amplified to provide a largerotation output to the drive shaft by a light force, and rotates thepinion gear.

The brake mechanism is arranged in such a manner that the drive shaftprotrudes inward of the one end frame 6 a from the brake memberarrangement hole 55 in a state that the brake member protrudes outwardof the one end frame 6 a.

Then, the pinion gear 25 is mounted to the end (the side arranged insidethe one end frame 6 a) of the drive shaft.

The brake member arrangement hole 55 is a through-hole formed in the oneend frame 6 a, and is formed slightly closer to the vehicle front sidethan the link assembling hole 51.

“The link driving member” in the embodiments refers to the brakemechanism (the pinion gear 25, the drive shaft, and the brake member)for example, and “the height adjustment mechanism mounting part formedas a hole part in which a link driving member is arranged” refers to thelink member arrangement hole 55.

Next, a mounting structure of the reclining mechanism 10 to the outsidesurface 22 b of the side frame 22 will be described.

When mounting the reclining mechanism 10 to the side frame 22, thereclining mechanism 10, more specifically, an outer surface 12 c of theinner case piece 12 b, is connected and fixed to the outside surface 22b of the side frame 22. Here, whereas the material of the inner casepiece 12 b is metal, the material of the side frame 22 is CFRP, so thatit is difficult to fix by welding when connecting and fixing the case 12of the reclining mechanism 10 to the outside surface 22 b of the sideframe 22.

Thus, in the process of manufacturing the vehicle seat S of the presentembodiment, a method in which the side frame 22 and the side part frames6 a, 6 b are coupled by mounting the case 12 of the reclining mechanism10, of the outside surface 22 b of the side frame 22, to a portion towhich the reclining mechanism 10 is mounted, and the configuration ofthe side part frames 6 a, 6 b will be described.

Method of Coupling the Side Frame 22 and the Side Part Frames 6 a, 6 b)

Next, with reference to FIGS. 11 to 21, a method of coupling the sideframe 22 and the side part frames 6 a, 6 b will be described.

Main configurations are similar on both sides, and therefore a method ofcoupling the side frame 22 and the side part frame 6 a (the one endframe 6 a) via the reclining mechanism 10 will be described.

In addition, in this configuration example, the coupling bracket 9 isalso used on the side part frame 6 b (the other end frame 6 b) but isnot limited thereto, the coupling bracket 9 may not be used on the sidepart frame 6 b (the other end frame 6 b).

Further, in FIGS. 11 to 21, the illustration of the reclining mechanism10 or the like is simplified for illustrative purposes (The details ofinternal structure or the like are as described above).

As shown in FIGS. 11 and 12, the coupling bracket 9 is coupled to therear end of the side part frame 6 a, and via the coupling bracket 9 andthe reclining mechanism 10, the side frame 22 is mounted to the sidepart frame 6 a.

In the present embodiment, the coupling bracket 9 is laser-welded to theside part frame 6 a.

However, the coupling bracket 9 is not limited thereto and may bemounted thereto by adhesives.

In addition, in the present embodiment, the reclining mechanism 10 alsois laser-welded to the side frame 22.

Similarly, the reclining mechanism 10 also may be mounted thereto byadhesives.

As thus described, in the present embodiment, the reclining mechanism 10is mounted to the outside surface 22 b of the side frame 22 by laserwelding or adhesives so that the mounting of the reclining mechanism 10can be easily performed without complicating the structure for mountingthe reclining mechanism 10 to the side frame 22, as in the case wherethe reclining mechanism 10 is over-molded into the frame at the time ofmolding of the seat back frame 1, for example.

First, as shown in FIGS. 13 and 14, the reclining mechanism 10 ismounted to the circular ring shaped mounting bracket 10 a.

This is performed as follows: the outer peripheral part of positioningprojections 12 d protruding outward from the outer surface 12 c of theinner case piece 12 b is assembled in a locked state to the innerperipheral part of a mounting hole 100 a formed in the center part ofthe mounting bracket 10 a. After that, of the outer surface 12 c of theinner case piece 12 b, a non-projection region 12 e (an outer peripheralportion) where the positioning projections 12 d are not formed islaser-welded to the peripheral part of the mounting hole 100 a of themounting bracket 10 a.

This welding point is shown by R1.

Next, as shown in FIGS. 15 and 16, the mounting bracket 10 a to whichthe reclining mechanism 10 is mounted is laser-welded to the outerperipheral portion of the reclining mechanism arrangement hole 22 aformed in the side frame 22.

In this example, the iron plate piece I1 of a circular ring shape ismounted to the reclining mechanism arrangement hole 22 a.

The iron plate piece I1 is constituted by having an inner peripheraliron plate piece I11 and an outer peripheral iron plate piece I12.

The inner peripheral iron plate piece I11 is a circular ring shaped ironplate, and is configured so that an outer peripheral diameter thereof isalmost identical to the reclining mechanism arrangement hole 22 a.

In addition, the outer peripheral iron plate piece I12 is a circularring shaped member, and is configured so that an inner peripheraldiameter thereof is almost identical to the reclining mechanismarrangement hole 22 a.

The outer peripheral iron plate piece I12 is concentrically layered sothat the inner peripheral diameter portion thereof aligns with the outerperipheral portion of the inner peripheral iron plate piece I11.

Therefore, as shown in FIG. 16, the cross-sectional shape of the ironplate piece I1 is a shape in which a step of the thickness of the innerperipheral iron plate piece I11 is formed. Then, it is configured sothat the thickness of the step and the thickness of the lower end of theside frame 22 are almost identical.

In other words, the iron plate piece I1 is engaged with the recliningmechanism arrangement hole 22 a by the step, and the outer peripheraliron plate piece I12 is insert-molded therein in a form that it extendsto the outside surface of the side frame 22.

Then, the mounting bracket 10 a to which the reclining mechanism 10 ismounted is welded to the outside surface of the outer peripheral ironplate piece I12.

This welding point is shown by R2.

In addition, with reference to FIG. 17, the welding connection of theside frame 22 molded by CFRP and the mounting bracket 10 a which is ametal member will be briefly described.

In the present embodiment, the iron plate piece I1 is used forconnecting by welding CFRP which is a resin and a metal.

In other words, the iron plate piece I1 is insert-molded in the weldingpoint of CFRP which is a resin, and the outer peripheral iron piece I12is exposed as a weld surface.

Then, the mounting bracket 10 a which is a metal is welded to thatportion, thereby connecting the both.

As thus configured, a resin material and a metal material which aredifferent materials can be coupled by welding, and the rigidity of thatportion is also improved because the iron plate piece I1 isinsert-molded therein.

Next, as shown in FIGS. 18 and 19, the metallic coupling bracket 9 islaser-welded to the reclining mechanism 10 mounted to the side frame 22and the rear end of the side part frame 6 a.

This coupling bracket 9 corresponds to “the coupling member”.

This coupling bracket 9 is configured with a bottom surface part 91 andan outer peripheral edge part 92.

As to the bottom surface part 91, its outer periphery is partly curvedin an arc shape to conform to a part of the outer periphery of thereclining mechanism 10, and from that portion, an extended portion toconform to the shape of the rear end of the side part frame 6 a isformed.

Then, the outer peripheral edge part 92 extending while bendingsubstantially vertically with respect to the bottom surface part 91 isformed along the arc shaped portion and the extended portion from thatportion to conform to the shape of the rear end side of the side partframe 6 a.

In other words, the outer peripheral edge part 92 is configured toextend along the upper edge of the rear end of the side part frame 6 afrom the upper portion of the reclining mechanism 10 and cover thatportion.

In addition, the height (the distance from the bottom surface part 91)of the outer peripheral edge 92 is configured to be almost identical tothe thickness of the reclining mechanism 10, and therefore it ispossible to secure the space in which the reclining mechanism 10 ispresent.

Further, a circular hole part 91 a is formed in the bottom surface part91 so that the outer surface of the outer case piece 12 a is exposed.

Hereinafter, the extended portion conforming to the shape of the rearend of the side part frame 6 a and constituting the coupling bracket 9is described as “a side part frame mounted part 91 b”.

The coupling bracket 9 is disposed to cover the position where the holepart 91 a is formed and the arc portion of the upper part thereof toalign with the reclining mechanism 10 welded to the side frame 22, andis disposed to cover the side part frame mounted part 91 b to align withthe rear end of the side part frame 6 a.

In this state, the peripheral portion of the hole part 91 a and theouter case piece 12 a are welded (this welding point is marked as R3),and the side part frame mounted part 91 b and the rear end of the sidepart frame 6 a are welded (this welding point is marked as R4).

The side part frame mounted part 91 b has a shape which is curved toescape to the rear side (to overhang toward the front upper side) withrespect to the link assembling hole 51 when mounted to the rear end ofthe side part frame 6 a.

Therefore, when assembling the height adjustment mechanism 5, theinhibition of assembling work by the coupling bracket 9 can beeffectively prevented.

In addition, by curving the welding portion in this manner, the weldingarea can be secured large compared to the case where it is linearlyformed so that the mounting rigidity of the coupling bracket 9 isimproved.

Further, the coupling bracket 9 is configured so that the lower side(the side welded to the side part frame 6 a) has a larger area than theupper part.

Thereby, the welding area to the side part frame 6 a can be securedlarge, so that the mounting rigidity is further improved.

The rear end portion of the side part frame 6 a at this time will bedescribed.

As shown in FIGS. 18 to 21, the iron plate piece I2 is insert-molded inthe rear end portion of the side part frame 6 a.

In the present embodiment, the iron plate piece I2 is insert-moldedalong the shape of the rear end portion of the side part frame 6 a.

In other words, in the present embodiment, the iron plate piece I2 isinsert-molded from the outside surface of the rear end of the side partframe 6 a over the edge portion (corresponding to “the upper sidesurface”) extending while bending inward from the upper part of theoutside surface.

Therefore, the coupling bracket 9 is welded and connected at thecovering portion in a state that the iron plate piece I2 arranged overthe outside surface and the upper side surface of the rear end of theseat cushion frame is covered.

Therefore, the mounting rigidity of the coupling bracket 9 is furtherimproved.

Although the iron plate piece I2 is integral over the outside surfaceand the upper side surface, it may be configured to be insert-molded ina part of the outside surface and a part of the upper side surface(namely, to be insert-molded as a plurality of components).

In the present embodiment, as shown in FIG. 21A, a flat plate shapediron plate is inserted as the iron plate piece I2 but it is not limitedthereto, and the iron plate may be configured to have a step into asubstantially Z-shaped cross section as shown in FIG. 21B.

As thus configured, the face in a position exposed on the surface can beused as the weld surface, and the side buried inside contributes to theimprovement of the rigidity without affecting the appearance.

In addition, as noted above (as to FIG. 17), the welding connection ofthe side part frame 6 a molded by CFRP and the mounting bracket 9 whichis a metal member will be briefly described.

In the present embodiment, the iron plate piece I was used forconnecting by welding CFRP which is a resin and a metal.

In other words, the iron plate piece I2 is insert-molded in the weldingpoint of CFRP which is a resin, and the weld surface is exposed.

Then, the side part frame mounted part 91 b of the mounting bracket 9which is a metal is welded to that portion, thereby connecting both.

In this manner, as shown in FIG. 12, with the four welding points R1,R2, R3, and R4, the lower end of the side frame 22 and the rear end ofthe side part frame 6 a are rotatably coupled via the coupling bracket 9and the reclining mechanism 10.

As thus configured, assembling can be easily performed, and the numberof components is reduced because components such as fastening membersare not necessary so that an increase in size of the reclining mechanism10 can be suppressed, which is advantageous also in cost.

In addition, the side part frame mounted part 91 b extends to a positionto overlap the rear end of the link assembling hole 51 in the up anddown direction, in a state that the coupling bracket 9 is thus mountedthereto.

As thus configured, the rigidity in the vicinity of the link assemblinghole 51 is improved, and along with this, the rigidity of the heightadjustment mechanism 5 is improved.

Similarly, the iron plate piece I2 inserted in the position aligned withthe side part frame mounted part 91 b also extends to the position tooverlap the rear end of the link assembling hole 51 in the up and downdirection.

Hence, the rigidity in the vicinity of the link assembling hole 51 isfurther improved, and along with this, the rigidity of the heightadjustment mechanism 5 is further improved.

The outer surface 12 c of the inner case piece 12 b is not limited tothe case where the positioning projections 12 d are formed thereon, andthe outer surface 12 c is not formed with the positioning projections 12d and may have a planar front face. In such a case, the welding area canbe increased by an amount that the positioning projections 12 d are notprovided, so that the reclining mechanism 10 can be favorably coupled tothe side frame 22 and can be stably disposed at the mounting position.

First Modification Example

Next, with reference to FIGS. 22 and 23, a first modification examplewill be described.

The first modification example is an example different in the area wherea second iron plate piece I102 is inserted.

Since the other configurations are similar to the above embodiment, adescription thereof will be omitted.

In this example, the area where the second iron plate piece I102 isinserted extends to the peripheral edge part of the link assembling hole51.

In other words, the second iron plate piece I102 is arranged (isinsert-molded) to surround the periphery of the link assembling hole 51.

As thus configured, the rigidity in the vicinity of the link assemblinghole 51 is improved, and the rigidity of the height adjustment mechanism5 is improved.

FIG. 23 shows a cross-sectional view taken along the line C-C of FIG.22.

FIG. 23A is in a state that the iron plate piece I102 is notinsert-molded.

In this example, as shown in FIG. 23B, the iron plate piece I102 isinsert-molded to be arranged in the periphery of the link assemblinghole 51.

However, this is not limited thereto, and as shown in FIG. 23C, the ironplate piece I102 may be insert-molded to wrap around to an inner wallportion of the link assembling hole 51.

As thus configured, the rigidity of the link assembling hole 51 isfurther improved.

Since the link assembling hole 51 is a hole in which the rear side link30 (the sector gear 31) of the height adjustment mechanism 5 isjournaled, it is preferable that further rigidity can be secured.

Second Modification Example

Next, with reference to FIG. 24, a second modification example will bedescribed.

The second modification example is an example different in the areawhere a third iron plate piece I202 is inserted.

Since the other configurations are similar to the above embodiment, adescription thereof will be omitted.

In this example, the area where the third iron plate piece I202 isinserted extends to the peripheral edge part of the brake memberarrangement hole 55.

As thus configured, the rigidity in the vicinity of the brake memberarrangement hole 55 is improved, and the rigidity of the heightadjustment mechanism 5 is improved.

Since the brake member arrangement hole 55 is a hole in which the piniongear 25 with the brake member is journaled, it is preferable thatfurther rigidity can be secured.

The configurations of the periphery and the inner wall surface of thebrake member arrangement hole 55 are similar to FIG. 23.

Third Modification Example

Next, with reference to FIG. 25, a third modification example will bedescribed.

The third modification example is an example different in the area wherea fourth iron plate piece I302 is inserted.

Since the other configurations are similar to the above embodiment, adescription thereof will be omitted.

In this example, the area where the fourth plate piece I302 is insertedextends to the peripheral edge parts of the link assembling hole 51 andthe brake member arrangement hole 55.

As thus configured, the rigidity in the vicinity of link assembling hole51 and the brake member arrangement hole 55 is improved, and therigidity of the height adjustment mechanism 5 is improved.

Since the link assembling hole 51 is a hole in which the rear side link30 (the sector gear 31) of the height adjustment mechanism 5 isjournaled, it is preferable that further rigidity can be secured.

Further, since the brake member arrangement hole 55 is a hole in whichthe pinion gear 25 with the brake member is journaled, it is preferablethat further rigidity can be secured.

The configurations of the periphery and the inner wall surface of thelink assembling hole 51 and the brake member arrangement hole 55 aresimilar to FIG. 23.

Fourth Modification Example

With reference to FIG. 26, a fourth modification example will bedescribed.

In this example, the rear end portion of the side part frame 6 a ismodified.

As shown in the above FIGS. 18 to 21, the iron plate piece I isinsert-molded in the rear end portion of the side part frame 6 a.

In this example, although a fifth iron plate piece I402 is insert-moldedalong the shape of the rear end portion of the side part frame 6 a, thecross-sectional shape thereof is modified as shown in FIG. 26.

In other words, the fifth iron plate piece I402 has a shape in which across-sectional convex part I402 a protruding to the coupling bracket 9side is formed, and the cross-sectional convex part I402 a portion isinsert-molded in the side part frame 6 a.

Then, a top surface portion I402 b of the cross-sectional convex partI402 a is exposed to the coupling bracket 9 side, and the couplingbracket 9 is welded and connected at a covering portion (a welding pointR5) in a state that the top surface portion I402 b is covered.

Therefore, the mounting rigidity of the coupling bracket 9 is furtherimproved.

In addition, as thus configured, the face in a position exposed on thesurface can be used as the weld surface, and the side arranged inwardcontributes to the improvement of the rigidity without affecting theappearance.

Fifth Modification Example

With reference to FIG. 27, a fifth modification example will bedescribed.

In this example, the rear end portion of the side part frame 6 a ismodified.

In the above FIGS. 18 to 21, the iron plate piece I was insert-molded inthe rear end portion of the side part frame 6 a.

However, in this example, an iron pin I502 is used instead of the ironplate piece I.

A frame-side iron pin through-hole H1 is appropriately formed in therear end portion of the side part frame 6 a, and the iron pin I502 isfixed to the frame-side iron pin through-hole H1.

In other words, the iron pin I502 is fixed in such a manner that thehead of the iron pin I502 is arranged inward and the free end side ofthe leg protrudes outward (to the coupling bracket 9 side).

Then, of the coupling bracket 9, a bracket-side iron pin through-hole H2is formed in a position aligned with the iron pin through-hole H1, thecoupling bracket 9 is disposed to cover the rear end portion of the sidepart frame 6 a so that the frame-side iron pin through-hole H1 and thebracket-side iron pin through-hole H2 are communicated with each other,and the leg of the iron pin I502 is inserted through the bracket-sideiron pin through-hole H2.

Next, a contact portion (a welding point R6) of the bracket-side ironpin through-hole H2 and the iron pin I502 is welded and connected.

Therefore, the mounting rigidity of the coupling bracket 9 is furtherimproved.

In addition, as thus configured, the vicinity of the frame-side iron pinthrough-hole H1 and the bracket-side iron pin through-hole H2 isreinforced by the head of the iron pin I502 arranged inward, whichcontributes to the improvement of the rigidity.

DESCRIPTION OF REFERENCE NUMERALS

-   S: Vehicle seat-   S1: Seat back-   S2: Seat cushion-   S3: Headrest-   HP: Headrest pillar-   1 a, 2 a, 3 a: Cushion pad-   1 b, 2 b, 3 b: Skin material-   1: Seat back frame-   21: Upper frame-   22: Side frame-   22 a: Reclining mechanism arrangement hole-   22 b: Outside surface-   23: Lower frame-   2: Seat cushion frame-   6 a: Side part frame (One end frame)-   51: Link assembling hole (Height adjustment mechanism mounting part)-   53: Link assembling hole-   55: Brake member arrangement hole-   I1, I2: Iron plate piece (Metal member)-   I11: Inner peripheral iron plate piece-   I12: Outer peripheral iron plate piece-   I102: Second iron plate piece-   I202: Third Iron plate piece-   I302: Fourth iron plate piece-   I402: Fifth iron plate piece-   I502: Iron pin-   6 b: Side part frame (The other end frame)-   52: Link assembling hole-   54: Link assembling hole-   4: Slide rail mechanism-   4 a: Movable rail-   4 b, 4 d: Link support projection-   5: Height adjustment mechanism-   30: Rear side link-   25: Pinion gear-   31: Sector gear-   33: First rotatable arm-   34: Second rotatable arm-   35: Coupling pipe-   61: First shaft pin-   62: Second shaft pin-   40: Front side link-   41: Front side link member-   42: Coupling pipe-   65: Fifth shaft pin-   66: Sixth shaft pin-   7: Rear end-side coupling part-   8: Front end-side coupling part-   8 a, 8 b, 8 c: Concave part-   8 d: Leg support part-   9: Coupling bracket (Coupling member)-   91: Bottom surface part-   91 a: Hole part-   91 b: Side part frame mounted part-   92: Outer peripheral edge part-   10: Reclining mechanism-   11: Reclining mechanism main body-   12: Case-   12 a: Outer case piece-   12 b: Inner case piece-   12 c: Outer surface-   12 d: Positioning projection-   12 e: Non-projection region-   13: Engaging gear-   14: Lock gear part-   15: Sliding lock member-   16: Path regulating part-   17: Cam surface-   18: Cam body-   19: Spring body-   20: Rotary shaft-   10 a: Mounting bracket-   100 a: Mounting hole-   H1: Frame-side iron pin through-hole-   H2: Bracket-side iron pin through-hole-   K1, K2: Locking part-   P: Spiral spring-   P1: One end-   P2: The other end-   R1, R2, R3, Welding point R4:-   T: Operating lever

1. A vehicle seat comprising: a seat back frame on which a recliningmechanism is arranged at a lower part thereof; and a seat cushion framemade at least partly of a resin material, wherein the recliningmechanism arranged on a lower end side of the seat back frame and a rearend side of the seat cushion frame are coupled with a metallic couplingmember, a metal member is integrally formed on the rear end side of theseat cushion frame, and an upper part of the coupling member is mountedto the reclining mechanism, and a lower part of the coupling member iswelded and connected to the metal member provided on the rear end sideof the seat back frame.
 2. The vehicle seat according to claim 1,wherein the metal member is arranged on at least a part of an outsidesurface of a rear end of the seat cushion frame and on at least a partof an upper side surface extending while bending inward from an upperpart of the outside surface, and the coupling member is welded andconnected at a covering portion in a state that the metal member portionarranged on the outside surface and the upper side surface of the rearend of the seat cushion frame is covered.
 3. The vehicle seat accordingto claim 1, wherein the seat cushion frame is provided with a heightadjustment mechanism mounting part to which a height adjustmentmechanism for displacing a height of the seat cushion frame with respectto a vehicle floor is mounted, and the coupling member extends to aposition aligned with at least a part of the height adjustment mechanismmounting part in an up and down direction in a state that the couplingmember is welded to the rear end side of the seat cushion frame.
 4. Thevehicle seat according to claim 3, wherein the height adjustmentmechanism is configured as a link mechanism, the height adjustmentmechanism mounting part is provided as a hole part in which a linkcentral axis or a link driving member is arranged, and the metal memberextends to a position where the height adjustment mechanism mountingpart is provided.
 5. The vehicle seat according to claim 4, wherein thecoupling member is configured by being curved in such a manner that amounting point thereof to the seat cushion frame extends toward a frontupper side of the seat cushion frame in a state that the coupling memberis welded to the rear end side of the seat cushion frame, and the metalmember is arranged by being curved to align with a shape of the mountingpoint of the coupling member to the seat cushion frame.
 6. The vehicleseat according to claim 1, wherein the seat cushion frame is providedwith a height adjustment mechanism mounting part to which a heightadjustment mechanism for displacing a height of the seat cushion framewith respect to a vehicle floor is mounted, and the metal member extendsto a position aligned with at least a part of the height adjustmentmechanism mounting part in an up and down direction.
 7. The vehicle seataccording to claim 1, wherein the coupling member and the recliningmechanism are welded and connected, and an upper part of the couplingmember is formed to align with a shape of the reclining mechanism, and awelded portion between the coupling member and the reclining mechanismis configured to align with the shape of the reclining mechanism.
 8. Thevehicle seat according to claim 1, wherein the reclining mechanism ismounted to the upper part of the coupling member, and the seat cushionframe is welded and connected to the lower part of the coupling member,and the lower part of the coupling member is configured larger than theupper part thereof.
 9. The vehicle seat according to claim 1, whereinthe seat cushion frame is provided with a height adjustment mechanismmounting part to which a height adjustment mechanism for displacing aheight of the seat cushion frame with respect to a vehicle floor ismounted, the height adjustment mechanism is configured as a linkmechanism, and the height adjustment mechanism mounting part is providedas a hole part in which a link central axis or a link driving member isarranged, and the lower part of the coupling member is curved to escapeto a rear side with respect to the height adjustment mechanism mountingpart when mounted to the rear end side of the seat cushion frame. 10.The vehicle seat according to claim 1, wherein the seat cushion frame isprovided with a height adjustment mechanism mounting part to which aheight adjustment mechanism for displacing a height of the seat cushionframe with respect to a vehicle floor is mounted, the height adjustmentmechanism is configured as a link mechanism, and the height adjustmentmechanism mounting part is provided as a hole part in which a linkcentral axis or a link driving member is arranged, and the metal memberprovided on the rear end side of the seat back frame extends to aposition surrounding the height adjustment mechanism mounting part. 11.The vehicle seat according to claim 1, wherein the seat cushion frame isprovided with a height adjustment mechanism configured as a linkmechanism for displacing a height of the seat cushion frame with respectto a vehicle floor, the height adjustment mechanism is provided with abrake pinion mechanism for restricting an action of the link mechanism,the seat cushion frame is provided with a brake member arrangement holein which the brake pinion mechanism is arranged, and the metal memberprovided on the rear end side of the seat back frame extends to aposition surrounding the brake member arrangement hole.
 12. The vehicleseat according to claim 1, wherein the metal member is arranged on atleast a part of an outside surface of a rear end of the seat cushionframe and on at least a part of an upper side surface extending andbending inward from an upper part of the outside surface, at least apart of the metal member is formed as a convex part protruding outward,at least a part of the convex part is exposed outward, and the couplingmember is welded and connected to an outward exposed portion of theconvex part in a state that the metal member portion arranged on theoutside surface and the upper side surface of the rear end of the seatcushion frame is covered.
 13. The vehicle seat according to claim 1,wherein the metal member is configured as an iron pin comprising a headand a leg, the iron pin is fixed to the seat back frame in such a mannerthat the head is arranged inward and a free end side of the leg isarranged outward, the coupling member is provided with a couplingmember-side iron pin through-hole through which the leg passes, and thecoupling member is mounted to the seat cushion frame by weldingconnection in a contact part of the leg and the coupling member-sideiron pin through-hole in a state that the metal member portion arrangedon an outside surface and an upper side surface of a rear end of theseat cushion frame is covered and the leg is inserted through thecoupling member-side iron pin through-hole.
 14. The vehicle seataccording to claim 1, wherein the metal member is arranged on at least apart of an outside surface of a rear end of the seat cushion frame andon at least a part of an upper side surface extending and bending inwardfrom an upper part of the outside surface and extends from a back towarda front of the outside surface while avoiding an upper edge part and alower edge part of the outside surface, and the coupling member iswelded and connected at a covering portion in a state that the metalmember portion arranged on the outside surface and the upper sidesurface of the rear end of the seat cushion frame is covered.